Convergence of molecular and morphological data reveals phylogenetic information on Tetranychus species and allows the restoration of the genus Amphitetranychus (Acari: Tetranychidae)

Abstract

AbstractNucleotide sequence variation and morphological characters were used to study the evolutionary relationships among nine tetranychid mites species. A phylogenetic study of this family based on mitochondrial cytochrome oxidase subunit I (COI) sequences had previously placed the species Tetranychus viennensis Zacher outside the other species analysed in the genus. Phylogenetic relations within the genus were re-examined with the addition of the species Tetranychus quercivorus Ehara & Gotoh, which is morphologically close to T. viennensis. Another region of the genome, the second internal transcribed spacer (ITS2) of ribosomal DNA, was also studied and proved to be of considerable interest at this taxonomic level. Both COI and ITS2 sequences indicated a close relationship between T. viennensis and T. quercivorus, which are grouped together and distinct from the other Tetranychus examined. The two species display morphological characteristics such as the absence of a medio-dorsal spur on all empodia of the legs of both sexes and the presence of anastomosing peritremes. This distinguishes them from the other members of the genus Tetranychus. The convergence of molecular and morphological data suggests that T. viennensis and T. quercivorus should not be classified in the genus Tetranychus. It is proposed that the genus Amphitetranychus Oudemans should be restored for classification of these species. Finally, a key to the Tetranychini tribe genera with one pair of para-anal setae is presented.